CEL P0304 then sometimes it seems to go into limp mode

Just a bit of background, I retired from Mazda as a Master Tech and a service guild member 12 years ago. I know my way around and don't appreciate being talked down to. Now with that behind us, My daughter's 2013 CX-5 Sport is throwing a P0304 #4 misfire. So I do the logical things, like clean the MAF sensor, replace the plugs with OEM, and replace the coil with OEM. No change. Sprayed around the intake and monitored O2s couldn't see much change. Then while driving CEL comes on again and the engine has no power and dash lights come on and CE starts flashing. The engine has only been running for about 5 min. Shut off the engine and restart. now the engine is smooth and dash lights are out. I'm leaning towards EGR or possibly lifter. So before I jump in and start ripping things apart, I thought I'd run it by here. Thanks for taking the time to read.
 
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GA prior 16 CX5 GT
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20 CX5 GT + Prem
Sometimes weak battery gives errors, even if new it could be weak so test it and check cables and grounds.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
Just a bit of background, I retired from Mazda as a Master Tech and a service guild member 12 years ago. I know my way around and don't appreciate being talked down to. Now with that behind us, My daughter's 2013 CX-5 Sport is throwing a P0304 #4 misfire. So I do the logical things, like clean the MAF sensor, replace the plugs with OEM, and replace the coil with OEM. No change. Sprayed around the intake and monitored O2s couldn't see much change. Then while driving CEL comes on again and the engine has no power and dash lights come on and CE starts flashing. The engine has only been running for about 5 min. Shut off the engine and restart. now the engine is smooth and dash lights are out. I'm leaning towards EGR or possibly lifter. So before I jump in and start ripping things apart, I thought I'd run it by here. Thanks for taking the time to read.
Read this thread which had almost the same problem like yours, the resolution was a set of expensive (ion-sensing) genuine Mazda OEM spark plugs (not even the NGK!) after all the effort he had done:

CX-5 2.0L - P0304 P0171 - Help needed please
 
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South Carolina
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12 MZ5 13 CX-5
Read this thread which had almost the same problem like yours, the resolution was a set of expensive (ion-sensing) genuine Mazda OEM spark plugs (not even the NGK!) after all the effort he had done:

CX-5 2.0L - P0304 P0171 - Help needed please
That is an amazing read! I had no idea about the ion sensing, never even heard of it before. I just did the plugs in my '13 CX5 with the 2.0 using NGK Laser Iridium's (ILKAR7L11 which claims to be the actual OE plug). So far, so good.
 
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2020 CX-5 AWD
That is an amazing read! I had no idea about the ion sensing, never even heard of it before. I just did the plugs in my '13 CX5 with the 2.0 using NGK Laser Iridium's (ILKAR7L11 which claims to be the actual OE plug). So far, so good.
It didn't surprise me to read that the problem in the thread yrwei52 posted was resolved by replacing the Bosch plugs. I've spent lots of time on the Dodge Caravan forums over the years, and Bosch plugs are notorious for causing problems in these vans, with a huge amount of negative feedback showing up about those plugs.

And I'd also suspect that those NGK plugs that you installed will be perfectly ok, and that paying that outrageous price for stealership plugs is not necessary. I've had good success with every NGK part I've used over the years, and if they describe them as OE, I'd put my trust in that.
 
Interesting read, "you learn something new each day". But I replaced the plugs with OEM original plugs ILKAR7L11 as a first step and I tried moving the original coil and plug to a different cyl with no change in performance.
After doing some research on this biased current at the spark plugs, I'm toying with the notion of if one of the intake valves isn't opening all the way or not at all it could change the electrical bias the PCM is looking for, making it seem richer that it is supposed to be. Also may pull the intake off and check for carbon buildup on the backside of the intakes, as it acts like a sponge soaking up fuel. I'll keep you posted on the results.

I appreciate the responses. You guys seem pretty knowledgable, unlike some of those lube monkeys at the dealer.
 
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2020 CX-5 AWD
,.. I'm toying with the notion of if one of the intake valves isn't opening all the way or not at all it could change the electrical bias the PCM is looking for, making it seem richer that it is supposed to be. Also may pull the intake off and check for carbon buildup on the backside of the intakes, as it acts like a sponge soaking up fuel. ....
I'm just a shade tree, who wouldn't normally second guess a pro, but I can't stop myself from asking about a compression/leak down test, before getting into the more time consuming work you mentioned above. But perhaps I'm one step behind (as usual) and you've already done one or both of those tests.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
Interesting read, "you learn something new each day". But I replaced the plugs with OEM original plugs ILKAR7L11 as a first step and I tried moving the original coil and plug to a different cyl with no change in performance.
Are you using NGK ILKAR7L11 / 94124 or Mazda genuine PE01-18110 / PE02-18110 or PE5R-18-110 / PE5S-18-110 spark plugs? And are you using Mazda genuine ignition coil or aftermarket ignition coil for replacement?
 
edmaz, I may have been a pro 20 yrs ago, but now just a retired Manufacturing Engineer. Back in the day, when you did a compression test, if you had a bad cyl or two it would affect the running quality. If all the cyls were bad you would see nothing and if they were all even you would never know you had a problem. So my summation is that it is running too smooth to have low compression. Plus it has less than 100K for mileage on a 10 yr old car. that see's it's oil changed every 3k. But they are both worthwhile endeavors so I may add them to my list of things to do, possibly when I pull the intake.
yrwei52, the plugs I purchased were PE5R-18-110 and the coil pack is OEM
 
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South Carolina
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12 MZ5 13 CX-5
There was also a thread recently about a motor where a rocker arm somehow fell off! If that happened to you, obviously that would cause a P0304 as well.
 

AVC

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'17 CX-5 Select
It could be *somewhat* low compression that causes a miss under some conditions, but permits smooth idle--freeze frame data? As these engines are DI and you've clocked 100k or so (I gather), it may indeed be carbon build up in intake valves. The intake manifold is actually easy to remove, once you get all the &*@^#&) wiring harness clips loose. If you have an amp clamp to a scope, or scope to measure starter voltage drop on WOT cranking, you could get a quick relative compression check before dismantling things.
 
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2014 Mazda CX-5 GT AWD w/Tech
Still want to know the status of the battery as that causes so many seemingly unrelated issues.
 

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